Moral skepticism is at present a vibrant topic of philosophical inquiry. Particularly since the turn of the millennium, the debates between moral skeptics of various stripes and their opponents have gained renewed force not only by taking account of innovative ideas in moral philosophy, but also by drawing on novel positions in epistemology, metaphysics, and philosophy of language as well as on recent findings in empirical sciences. As a result, new arguments for and against moral skepticism have been devised, while the traditional ones have been reexamined. This collection of original essays will advance the ongoing debates about various forms of moral skepticism by discussing such topics as error theory, disagreement, constructivism, non-naturalism, expressivism, fictionalism, and evolutionary debunking arguments. It will be a valuable resource for academics and advanced students working in metaethics and moral philosophy more generally.